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Enhanced photovoltaic energy conversion using thermally based spectral shaping


Solar thermophotovoltaic devices have the potential to enhance the performance of solar energy harvesting by converting broadband sunlight to narrow-band thermal radiation tuned for a photovoltaic cell. A direct comparison of the operation of a photovoltaic with and without a spectral converter is the most critical indicator of the promise of this technology. Here, we demonstrate enhanced device performance through the suppression of 80% of unconvertible photons by pairing a one-dimensional photonic crystal selective emitter with a tandem plasma–interference optical filter. We measured a solar-to-electrical conversion rate of 6.8%, exceeding the performance of the photovoltaic cell alone. The device operates more efficiently while reducing the heat generation rates in the photovoltaic cell by a factor of two at matching output power densities. We determined the theoretical limits, and discuss the implications of surpassing the Shockley–Queisser limit. Improving the performance of an unaltered photovoltaic cell provides an important framework for the design of high-efficiency solar energy converters.

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Figure 1: Operating principle of STPVs and comparison with solar PVs.
Figure 2: Theoretical performance of a thermal spectral converter.
Figure 3: Spectrally engineered STPV device.
Figure 4: Experimental results of efficiency and heat generation.
Figure 5: Nanophotonic material set in the radiative limit.


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This work was supported as part of the Solid-State Solar Thermal Energy Conversion (S3TEC) Center, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Basic Energy Sciences under Award no. DE-FG02-09ER46577. The authors thank C. Wang from Lincoln Laboratory for providing the InGaAsSb cells; H. Mutha, D. Li and C.V. Thompson’s group (for help with CNT growth); W. Lee and IDAX Microelectronics Labs, Inc. (PV cell packaging); K. Broderick and Microsystems Technology Laboratories (spectral converter/aperture fabrication); K. Bagnall and J. Tong (optical configuration advice); the Device Research Lab (for critique); M. N. Luckyanova, G. Chen and the Nanoengineering group (for advice and experimental aid).

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Authors and Affiliations



All authors contributed extensively to this work. D.M.B. and A.L. designed the experimental and theoretical studies, constructed the experimental model, and wrote the paper. D.M.B. and B.B. designed and fabricated components for the device scale-up. D.M.B. wrote the code for the theoretical study and executed the experiments. W.R.C. designed and fabricated the emitter. I.C., M.S. and E.N.W. supervised and guided the project.

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Correspondence to Evelyn N. Wang.

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The authors declare no competing financial interests.

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Supplementary Note 1, Supplementary Figures 1–5 and Supplementary References. (PDF 684 kb)

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Bierman, D., Lenert, A., Chan, W. et al. Enhanced photovoltaic energy conversion using thermally based spectral shaping. Nat Energy 1, 16068 (2016).

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